George Osborne, the chancellor. The letters are being sent to more than 24 million people at a cost of £5m. Photograph: Will Oliver/EPA

George Osborne has been criticised for sending millions of households annual tax statements that show the biggest chunk of their contribution going towards welfare, with trade unions describing it as “political propaganda masquerading as neutral information”.

The letters are due to fall on to doormats over the next few weeks but the Treasury has quietly dropped plans to provide a further breakdown of benefit spending on the document.

The annual tax statements, announced by the chancellor in March 2012, are to provide more than 24 million people with a visual illustration of how their taxes are being spent. In examples released by the Treasury, someone earning £30,000 a year would be told that £1,663 of their money goes towards welfare, £1,280 to health, £892 on education, and £822 to state pensions. Just £78 of their taxes goes towards overseas aid and £51 to the EU budget.

The letters are being sent – at a cost of £5m – after Osborne signalled that he wanted to make another £12bn of welfare cuts in the next parliament, raising suspicions that he is seeking to soften up voters in order to win political support for further reductions in the benefits budget.

On Monday, the TUC criticised the chancellor’s motives for sending out the statements. Frances O’Grady, the union’s general secretary, said: “The chancellor is relying on the fact that many people think spending called welfare all goes to the unemployed. This is softening us up to a major cut to the welfare state safety net to which we all should contribute so that it is there if we need it.”

The breakdown does not make clear that most of the welfare budget goes to pensioners as well as sick and disabled people. The Treasury originally planned to show that just 3% went towards unemployment benefits, while much larger amounts went to children and families, elderly people and those unable to work.

A Treasury spokesman said the 2012 version had just been a prototype and that after research it was decided to simplify the summaries. A more detailed breakdown was available on the government’s website.

Dame Anne Begg, chair of the Commons work and pensions committee, said it appeared to be part of a trend in the presentation of figures as the coalition had tried to “make the phrase welfare almost appear as a dirty word”.

She said: “If they are presenting welfare in this statement as one homogeneous figure, it includes a lot of welfare spend that most people in the country agree with.

“My select committee has been very critical of the way the government, usually the DWP, presents its information about welfare, which gives people the impression the bulk of welfare goes to working-age unemployed people when in reality that is a very small proportion. The vast majority of the budget goes to people that includes people with severe disabilities and the poorest pensioners. Generally the public supports welfare going to those people who have the least.”

Sheila Gilmore, Labour MP for Edinburgh East, who also sits on the Commons work and pensions committee, said annual statements about taxes were “not a bad thing but it matters how you do it”.

“To lump all of welfare together, given people’s understandable lack of knowledge about where it goes, is designed to make people think ‘oh, it’s terrible, shocking, far too much’ and presumably endorse whatever further tightening up the government is proposing,” she said.

Shabana Mahmood, the shadow Treasury minister, said the statements did not show that “families and pensioners are paying more in higher VAT. Independent figures from the IFS [Institute for Fiscal Studies] show that by next year families will be £974 a year worse off because of tax and benefit changes since 2010.”

Osborne said it was a revolution in transparency over how people’s money was being used by the government.

“I promised that taxpayers would know much more about how much direct tax they pay and how that money is spent,” he said. “Now we’re delivering on that promise by giving 24 million taxpayers a new personal tax summary. It is a revolution in transparency and it will show how hardworking taxpayers have to pay for what governments spend.”

Around eight million taxpayers who complete self-assessment returns will be able to access their tax summary online, while the 16 million PAYE taxpayers who received a tax coding notice from HMRC for 2013 to 2014 will receive their summary in the post over the next seven weeks.